Various types of domestic food cooking apparatus are known in the art. In the domestic cooking art, there are known various automated cooking devices including mechanical mixing apparatus.
The following patents are considered to be representative of the prior art:
U.S. Pat. No. 3,635,147 describes a combination cooking-stirring vessel in which two sets of blades are rotated continuously by means of a motor drive applied to the rim of a generally round bowl, as food is heated. One set of blades rotates along the bottom of the bowl except at the center bottom region.
U.S. Pat. No. 1,790,115 describes apparatus for treating food products comprising a plurality of rotating blades and a curved bottom surface.
U.S. Pat. No. 4,693,610 describes an electrical household appliance for culinary purposes including apparatus for stirring and heating the contents of a bowl. This apparatus provides continuous rotation of a stirrer adjacent the bottom of a flat bottomed bowl.
U.S. Pat. No. 4,649,810 describes microcomputer-controlled, integrated cooking apparatus for automatically preparing culinary dishes. The apparatus includes a memory for storing one or more recipe programs. The recipe program specifies schedules for dispensing the ingredients from a compartmentalized carousel into a flat bottomed cooking vessel, for heating the vessel and for continuously stirring the contents of the vessel.
U.S. Pat. No. 1,491,991 describes a beverage mixer and heater which provides stirring of the contents of a container having an electric heating element incorporated in its construction.
In an industrial environment, which is distinct from the domestic food cooking field discussed above, there have been proposed various devices which provide heating or cooling of food products. For example, U.S. Pat. No. 4,073,225 describes, on an industrial scale, a continuously operable meatball cooker employing a trough which is engaged by helical vanes. U.S. Pat. No. 3,407,872 employs a trough-like tank having a reciprocating paddle for circulating a heating or cooling fluid.
Italian patent 567138, granted Oct. 1, 1957, describes a mechanical agitator including first and second series connected mutually angled shafts, which are driven by a motor. The second shaft includes a fixed termination end which engages the inner surface of a container.
U.S. Pat. No. 4,629,843 describes induction cooking apparatus having a ferrite coil support and includes monitoring and control apparatus for preventing heating of the ferrite coil support above its Curie temperature.
U.S. Pat. No. 4,467,162 describes an arrangement for an induction heating process employing a shielding plate member of non-magnetizable metallic material disposed in a space between a heating coil and a bottom plate.
U.S. Pat. No. 3,761,668 describes a cooking system wherein small electrical appliances are powered by an induction cooking device.
U.S. Pat. No. 4,817,510 illustrates cooking apparatus wherein the temperature of cooked food is automatically controlled and varied during a cooking cycle.
U.S. Pat. No. 4,885,447 describes a system for induction heating of the electric plates of a cooker and employs an inverter bridge of MOS technology to provide a pulsating current.
U.S. Pat. No. 4,736,082 describes electromagnetic induction heating apparatus capable of preventing undesirable states of cooking utensils or vessels.
U.S. Pat. No. 4,549,056 describes electromagnetic induction heating apparatus capable of heating nonmagnetic cooking vessels and employs an AC field having a frequency of at least 50 KHz and preferably about 100 KHz, for heating non-magnetic materials such as aluminum. For magnetic materials, such as iron, a separate switching circuit and a separate coil provide an AC field having a significantly lower operating frequency. U.S. Pat. No. 4,749,836 describes electromagnetic induction cooking apparatus capable of providing a substantially constant input power, which includes features similar to those described above in connection with the apparatus of U.S. Pat. No. 4,549,056.
U.S. Pat. No. 4,792,652 describes an electric induction cooking appliance with reduced harmonic emission which employs a plurality of coils wound in opposite senses. U.S. Pat. No. 4,453,067 describes an induction heating coil having non-uniformly spaced turns.
U.S. Pat. No. 3,814,888 describes a solid state induction cooking appliance operating at ultrasonic frequencies.
U.S. Pat. Nos. 3,814,888; 4,296,295; 4,617,441; 4,667,074; 4,426,564; 3,761,668 and 3,742,179 all show induction heating systems for cooking and some show temperature measurement apparatus operative therewith.